Different memory scheduling policies have been proposed and implemented in recent years in the computer industry to improve performance of the memory subsystem. However, lately energy efficiency has become a first order consideration in designing memory subsystems. Thus, sometimes it is beneficial for certain computer systems to sacrifice some latency at times in the memory subsystem to improve upon overall power consumption of the memory subsystem as a whole.
Modern memory modules are normally divided into several memory ranks, where each rank has several banks. Power delivery to memory subsystems can often be broken up to have power delivered independently for each memory rank. Computer systems with advanced power management features have the capability to have subsystems such as the memory subsystem brought into low power idle states as well as being in full power operational states.